Article: Justification, Faith and Works: Calvin on Ezekiel 18:17
by R. B. Gaffin, Jr., Professor of Biblical and Systematic Theology, Emeritus at Westminster Theological Seminary (original source here).

A passage from Calvin’s commentary on Ezekiel 18:14-17 has the distinction of being among the last, perhaps the last, of his comments on the relationship among justification, faith and works. Apparently written shortly before his death in 1564, it is perhaps as pointed as any of his comments on their interrelationship and so, highly instructive concerning his matured understanding. An excerpt of some length from his comments on verse 17 is provided here, because, seen in its immediate context, it needs to be read carefully and digested (bolding added). Note that when Calvin speaks here of “works” he clearly has in view, as the plural shows, the believer’s good works or obedience done over time, in other words, seen in terms of God’s work in the believer, sanctification as ongoing or progressive, what he regularly includes elsewhere with “regeneration,” a word he uses in a broader sense than later Reformed theology.

When therefore, we say that the faithful are esteemed just even in their deeds this is not stated as a cause of their salvation, and we must diligently notice that the cause of salvation is excluded from this doctrine; for, when we discuss the cause, we must look nowhere else but to the mercy of God, and there we must stop. But although works tend in no way to the cause of justification, yet, when the elect sons of God were justified freely by faith, at the same time their works are esteemed righteous by the same gratuitous liberality. Thus it still remains true, that faith without works justifies, although this needs prudence and a sound interpretation; for this proposition, that faith without works justifies is true and yet false, according to the different senses which it bears. The proposition, that faith without works justifies by itself, is false, because faith without works is void. But if the clause “without works” is joined with the word “justifies,” the proposition will be true. Therefore faith cannot justify when it is without works, because it is dead, and a mere fiction. He who is born of God is just, as John says (1 John v. 18). Thus faith can be no more separated from works than the sun from his heat: yet faith justifies without works, because works form no reason for our justification; but faith alone reconciles us to God, and causes him to love us, not in ourselves, but in his only-begotten Son.

Taken by itself, Calvin considers the statement “faith without works justifies” to be ambiguous. It “needs prudence and sound interpretation”; it is “true yet false,” depending on the way it is read. Pinpointed grammatically, Calvin is saying:

When the prepositional phrase “without works” is taken adverbially, that is, as modifying the verb “justifies,” then the statement “faith without works justifies,” is true;
When “without works” is taken adjectivally, that is, with the noun “faith,” that is, “without-works faith,” then the same statement is false.

“Without-works” faith (alone-faith) Calvin asserts, does not justify, “because faith without works is void.” Again he says, “faith cannot justify when it is without works, because it is dead and a mere fiction.” He is saying in effect, to focus the balance of his remarks: “faith, with its works, justifies without works”; or also, “with-works faith (or “not-without-works faith”) justifies without works.” Alone-faith does not justify, but justification is by faith alone; faith is the alone instrument of justification.

In this passage Calvin is on the proverbial razor’s edge, where we occasionally find ourselves in sound theologizing faithful to Scripture. Certainly, he is not saying here what he emphatically and repeatedly denies elsewhere, that I must do a certain amount of good works or obey God for a certain amount of time before I can be justified or be sure that I am justified. Rather, his comments highlight that even in its initial exercise justifying faith is inherently disposed to obedience and good works, which are bound to come to expression, however imperfectly, over time. His point is what is expressed later in the Westminster Confession, namely that faith as “the alone instrument of justification” is “not alone in the person justified, but is ever accompanied with all other saving graces, and is no dead faith, but worketh by love”; or, more importantly, Paul’s characterization of justifying faith as “faith working through love” (Galatians 5:6; alluded to and cited as Scriptural support by the Confession at this point).

Here, in a particularly striking and instructive way, Calvin accents how inseparable, yet distinct, good works are from faith as the alone instrument of justification. This is fully in keeping with what he emphasizes in many other places, perhaps most notably at the beginning of his magisterial treatment of justification in the Institutes. With the application of redemption as the large, overall concern of Book Three, he had previously discussed sanctification (“regeneration”) and in considerable length (3:3-10). Why did he order his material in this way, treating sanctification before justification? “The theme of justification was therefore more lightly touched upon because it was more to the point to understand first how little devoid of good works is the faith, through which alone we obtain free righteousness by the mercy of God; and what is the nature of the good works of the saints, with which part of this question [justification] is concerned” (3:11:1).

Such works–it is surely true to Calvin to add–are necessary as “the fruits and evidences of a true and lively [that is, justifying] faith” (WCF, 16:2).